In general, in the cheese production process, a method is adopted in which pasteurized cow's milk or goat's milk is used as starting material milk, a lactic acid bacteria starter is added thereto to make the starting material milk acidic, a milk-coagulating enzyme such as chymosin is added to coagulate the milk protein casein, the coagulum (curd) and milk serum (whey) are separated, and the coagulum is matured to produce cheese. The above-mentioned milk-coagulating enzyme does not have sterilizing ability, and hence in general it is only acceptable to use pasteurized milk as the starting material milk.
In this way, with the conventional cheese production method, a method is adopted in which a lactic acid bacteria starter is added to the starting material milk, and once the pH has dropped to a prescribed level, rennet is added to coagulate the milk. With the conventional method, it is thus necessary to proliferate the starter lactic acid bacteria by repeating subculture a plurality of times from a stored strain. Moreover, the starter is added to a large amount of the starting material milk, and hence it is necessary to produce a large amount of a highly active mother starter. Furthermore, quality control must be carried out thoroughly such that there is no contamination with other unwanted bacteria when using the starter.
Moreover, to inoculate with the starter and attain the target pH, it is necessary, for example, to culture the starting material milk at 20° C. for at least several hours. Furthermore, rennet is added to coagulate the milk once the pH has dropped; this rennet is an enzyme taken from calves' stomachs, and is expensive. There is, on the other hand, a method of preparing rennet by culturing a microorganism, but as with the case of taking the rennet from calves' stomachs, this is expensive, and moreover there is a problem that the product becomes bitter.
In view of the prior art described above, it is a problem of the present invention to develop a novel technique enabling a high-quality cheese-like dairy product to be produced without using a starter or rennet as described above; according to the present invention, this problem can be solved by utilizing the functions of Paenibacillus sp. cells, instead of using a starter and rennet as described above.
The present invention provides a method of producing a high-quality cheese-like dairy product without using rennet, which is expensive, or a starter, as used in a conventional cheese production method, and a product thus produced.
The present invention relates to a method of producing a cheese-like dairy product, characterized by adding at least 10 wt %, relative to the starting material milk, of water containing Paenibacillus sp. bacteria or water that has been treated with immobilized cells of Paenibacillus sp. bacteria, into starting material milk, followed by maintaining at a prescribed temperature, separating off the curd thus formed, and performing productization with or without further manufacturing; a cheese-like dairy product thus produced; and a water purifier packed with a support having Paenibacillus sp. bacteria immobilized thereon and a filter medium as a packing material.